CONCORD, N.C. (AP) Standing next to his car in victory lane, in this season he never thought possible, Martin Truex Jr. struggled with his emotions.

He raced to his career-best sixth victory Sunday at Charlotte Motor Speedway, and this win is worth an automatic slot in the next round of NASCAR's playoffs. He's clearly the driver to beat in this championship race, and the reality of how close it really is seemed somewhat surreal.

Then he thought about his partner, Sherry Pollex, who has ovarian cancer and chemotherapy scheduled for Monday. She couldn't come to the race, partly because her weakened immune system makes crowds too risky for her.

He choked on his words, his voice heavy as he tried not to cry.

"I couldn't hold it in anymore," he said. "Sherry, I was thinking about her because she's not here, and I know she really wanted to be. I thought about winning this first race of the round, the pressure coming off. Just a lot of things, I guess. I was wore out. I just lost it for a minute.

"There's a lot going on. It just shows how much this stuff means to us. We put everything into this, everything we have."

Truex gave Toyota yet another victory in NASCAR's playoffs - the manufacturer is 4 for 4 so far - on a humid day at Charlotte. Truex has two wins in the playoffs and this one was the first time in this format that Toyota has won a race in this round of postseason.

"Just a total team effort," Truex said. "Every single guy, every guy on this team just did a perfect job today and I can't be more proud of them and at this time of the year is just when you want it to happen. You dream about days like today. I don't know if we had the best car, but we damn sure got it in victory lane."

Kyle Busch, winner of the last two playoff races, wrecked early in the race yet completed it in a damaged race car. Complaining most of the 500 miles of being overheated, he needed immediate medical attention when he climbed from his car.

Busch laid in the grass, packs of ice were placed on his chest, and a stretcher was brought to him. Once he felt strong enough, he stood and walked to an ambulance. He received oxygen to treat a high carbon monoxide level.

"I felt like I was having a heat stroke," Busch said.

The humidity drained several drivers, including Truex, who had to catch his breath after taking the checkered flag.

"Seeing him after the race, how whipped he was, was kind of a shock," crew chief Cole Pearn said.

Truex won in overtime after two late cautions created extra laps and forced Truex to hold off fellow Toyota driver Denny Hamlin on a pair of restarts.

Chase Elliott finished second for the second consecutive week and sixth time in his career. He nearly won for the first time in the Cup series a week ago, but Busch ran him down and passed him for the win with one lap to go.

Harvick was third and Hamlin finished fourth. Like his teammate Busch, Hamlin was drained after the race. His firesuit was soaked with sweat stains and he needed to eat a banana to recover.

"You usually can tell hydration level from my suit," Hamlin said. "Any time it has white streaks all over it, I'm spent pretty good. I feel pretty bad, no doubt about it."

PLAYOFF STANDINGS: The bottom four in the standings headed into Talladega are Kenseth, Keselowski, Blaney and Stenhouse. But, it could have been much worse for Stenhouse, who was all over the board Sunday until he solidly cracked the top-15 late in the race.

But, Stenhouse was busted for speeding on a late pit stop and had to restart 20th. He had to scramble in the closing laps to finish 13th.

"We thought if we could be 15th to 10th it would be a good day for us," he said. "It would be nice to run top-10 all race here, but we struggled up and down."

LUG NUT CONTROVERSY: Johnson was fourth when he headed to pit road under a Lap 280 caution. When crew chief Chad Knaus noticed a missing lug nut, Johnson slowed his exit from the pit box.

That technically counts as servicing the car outside the pit box, which warrants a one-lap penalty. But NASCAR did not punish the champion.

NASCAR spokesman Kurt Culbert said Johnson's stop was completed, and teams could work outside the stall if an unsecure lug nut was discovered after the stop. By stopping and backing up, NASCAR felt Johnson's team essentially had served its own penalty.

LARSON'S LONG DAY: His 10th-place finish gave no indication of how good Larson was at Charlotte. He seemed to be as good as Truex late in the race, but an awful pit stop - his tire carrier tripped and fell - dropped him to 12th. Larson still worked his way into the top-four, but he was hit by Kurt Busch late in the race and the damage took him out of contention for racing for the victory.

Earlier in the race, Larson missed his pit box and the gaffe knocked him to 31st in the field. But he clawed his way through traffic and had worked his way into the top five by the end of the first stage.

"I felt like we've been better than (Truex) the past two weeks," Larson said. "Last week was probably the first time in a long time he hasn't been the most dominant. And then, he definitely wasn't dominant today. I felt like I had a car to win. I made a mistake on pit road early. We rebounded from that. And then we had a costly mistake late and somewhat rebounded, but then those last two restarts didn't go my way."

UP NEXT: Sunday's race at Talladega Superspeedway, where Stenhouse won in the spring. Stenhouse has won the last two restrictor-plate races this season.